Combination rule and compass



Sept. 29, 1931. A. A. FISCHER PASS Filed Nov. 10 1928 Patentedsept. 29,1931 UNITED? STATES PATENT OFFICE Lemma 4'. mscm, or nmsnnmm, rumorscommunon .nULn comes I Application filed November 10, 1988. serial iio.818,320.

This invention relates to a combination rule and compass and moreparticularly to a device adapted for use inflayin out'cir cles and linesupon a schoolroom b ackboand or other plane surface. V I

The main object of the invention is the provision of an'adjustable meansfor de; scribing circles .or arcs thereof which may be :dsed upon theconventional rule or straightnother object of the invention is to provide a device of the above mentioned character which will be eflicientin operation and simple, cheap and durable in construction.

With the foregoing and other objects in view the invention resides inthe novel construction and arrangement of parts as hereinafter set forthand claimed.

In the drawings: 1 p 7 Figure 1 is a plan view ofthe invention partiallybroken away.

Figure '2 is an enlarged stion along the line 2-2 in Figure 1.

Figure 3 is a plan view of a modification of the invention, also shownpartially broken away; Figure' t is an enlarged section along the line4- 1 in Figure 3.

The invention consists of a pivotal element denoted generally at 1, thesame being rotatably mounted in the rule 2 adjacent one end thereof asshown in Figure 1. The said pivotal 'element 1 comprises the circularmetal plate 3 and the circular rubber plate 4 mounted in spacedrelationship upon the ends of a tubular spindle 5, the said plates 3 and4 being rotatably mounted in aligned recesses 6 cut inopposite faces ofthe rule 2 adjacent one end thereof and the spindle 5.

being rotatably mounted in a bore 7 through the rule and connecting thesaid recesses 6. Spaced apertures 8 are provided in the rule 2 inlongitudinal alignment with and spaced from the pivotal element 1. M i

In the use of the present embodiment of the invention the pivotalelement 1 'is positioned over any desired centeror point and heldinplace by the finger of the operator, the rubber constructionofvthecircular plate 4=facilitating the holding of the pivotal element uponthe proper point, it alsobeing noted that the said rubber plate 4.-projects slightly beyond the face of the rule 2 for this same purpose. Asuitable markin device (not shown) such as a pencil or cha is theninserted through one of the apertures 8 and by swlnging'or rotating the.rule 2 upon the said-pivotal assembly 1 a circle or are may bedescribed as will be understood. The tubular construction of the spindle5 affords a sight aperturefacilitating the proper locating of thepivotal element over the line or point. It will be noted that thepivotal element 1 and apertures 8 are positioned in lateral alignmentwith certain points upon the scale of the rule 2 so that the length ofthe radius of the are or circle being described'may be known.

In Figures 3 and 4 is shown a modification of the marking devicereceiving means for the. rule, the pivotal element (not shown in thisview) being identical with that previously described. In this embodimentthe rule 7 is provided-with a longitudinally extended slot 9 placedtoward that end of the rule opposite to the end in which the pivotalelement is mounted. A carrier or slide 10 is provided with grooves 11 inits parallel sides to slidably engage themargins of the slot 9 andthesaid carrier is also provided with a medial aperture 12 to receive asuitable marking device (not shown).

The use of this embodiment is the same as that set forth for the firstembodiment, the carrier 10 being susceptible of movements to differentpointstwithin the slot 9v to permit the drawing of circles of varioussizes.

While I have herein set forth certain pre-- ,ferred embodiments of myinvention, it is metal plate and a. circular rubber plate rotatablymounted in the recesses in the upper and lower faces respectively of therule and secured to the ends of the said tubular. spindle. p Intestimony whereof aifix my signature.

ARTHUR A. FISCHER.

